Significant use of the Recto-sigmoid Index in Prediction of Hirschsprung Disease in the Newborn Period
Nantika Siwaborwornwattana MD*, Monawat Ngerncham MD, MSPH* Kriengkrai Iemsawatdikul MD**, Mongkol Laohapensang BSc, MD*
Affiliation : * Division of Pediatric Surgery, Department of Surgery, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand ** Division of Pediatric Radiology, Department of Radiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
Objective : There has been a debate regarding the accuracy of contrast enema (CE) in the diagnosis of Hirschsprung disease
(HD) in the newborn period when a transitional zone (TZ) was not well demonstrated. The aim of this study is to determine
the optimal cut-point that will improve the accuracy of the recto-sigmoid index (RSI) and other positive CE signs in predicting
aganglionosis in the newborn period.
Material and Method: A retrospective review of newborn patients who underwent CE for suspected HD during a 3-year
period (2005 through 2008) was conducted. The RSI and other positive contrast enema signs were evaluated and compared
with pathological reports. Data were analyzed by Chi-square.
Results : Thirty-five neonates (20 M: 15 F, mean age: 19.5 days) underwent 37 preoperative CE. Aganglionosis was histologically
confirmed in 20 patients (54%). The most common site of proximal extent of aganglionosis was recto-sigmoid colon (9
patients, 45%). The results of pathology and CE were concordant in 91% of the patients for transitional zone (TZ) and 68%
for other CE findings. From the ROC curve, the most accurate diagnostic cut-point was RSI of the lateral view of <0.7
(sensitivity of 60% and specificity of 88.2%), whereas radiographic TZ had 50% sensitivity and 94% specificity. The
combination of radiographic TZ and/or RSI increased the sensitivity up to 70% and specificity to 82.4%. The inter-rater
reliability was 0.83 and 0.7 for 2 observers, while the intra-observer variation was 0.1.
Conclusion : RSI can improve the accuracy of CE for the diagnosis of HD in the newborn period. Further studies with larger
sample size are required to better confirm these findings.
Keywords : Hirschsprung disease, Contrast enema, Transitional zone, Recto-sigmoid index, Newborn
